Currently, the only seller of hybrid drives for consumer products is Seagate, which has been shipping its Momentus XT since 2009. Seagate is currently on its third generation of the Hybrid drive, its first being the Momentus PSD, which it launched in 2007.

Seagate's most recent Momentus XT drive comes in capacities of 500GB and 750GB.

Earlier this month, Western Digital announced it is sending out samples of its hybrid drive to laptop manufacturers. Western Digital said it's 5mm-thick hybrid drive has 500GB of storage capacity. Other than that, Western Digital release little information on the drive.

Like Toshiba's upcoming hybrid, Seagate's Momentus XT also comes with 8GB of NAND flash (in the 750GB model, 4GB in the 500GB model) and 32GB of RAM. Other than having a top drive capacity of 1TB, Toshiba's drive differs from Seagate's in that it uses a 5400RPM, two-platter hard disk drive; Seagate's Momentus XT uses a 7200RPM, which uses more power, Toshiba claimed. Unfortunately, Toshiba didn't provide power use information on it drive.

Toshiba's new hybrid drive is expected to ship in Q4 of 2013.

Both Toshiba's and Seagate's hybrid drives use the SATA 3.0 (6Gbps) interface.

Like Seagate's drive, the Toshiba hybrid comes in a standard z-height of 9.5-mm, or .37-in. thick.

Seagate's drive averages 1.3 watts of power during operation, and 1.1 watts while idle.

When it comes to performance, Toshiba was unable to provide performance metrics other than I/O's per second (IOPS) and seek times. Toshiba said its drive has an average seek time of 12 milliseconds, compared to the Momentus XT's 11ms read seek time and 13ms write time.

The Toshiba hybrid has a maximum 4,000 random IOPS using 4K block sizes. Without aid of the SSD element, the Toshiba hard dirve has a maximum data transfer speed of 1,469 Mbps or 184 MBps, said Kim.

"What we've done with our hybrid drive is fully married the benefits of Toshiba's knowledge of rotating media with the in-house expertise, IP and technology know-how in NAND flash," Kim said.

Hybrid drive adoption slow

Hybrid drive adoption has been unremarkable, said the market research firm IHS iSuppli. A report released earlier this year said that while sales of hybrid drives are expected to double over the next year, that increase cannot compare with sales of pure SSDs, which are expected to skyrocket 2,660%.

Hybrid drive shipments will reach just two million units this year, up from 1 million units in 2011. IHS iSuppli predicts hybrid drive shipments will reach 25 million units by 2016.

Pure SSDs are currently the leading storage type in ultrabooks, but low-capacity (20GB to 40GB) cache SSDs, which run along side hard drives in notebooks, will see shipments rise even more this year to 23.9 million units, up an astounding 2,660% from just 864,000 units in 2011. Shipments will then jump to 67.7 million units next year, cross the hundred-million-unit mark in 2015, and hit 163 million units by 2016, said IHS iSuppli.

Higher capacity, pure SSDs (with 80GB to 512GB capacity) will reach 18 million units shipped this year and 69 million by 2016, said iSuppli.

Toshiba scientist Fujio Masuoka invented both NAND and NOR flash memory in 1980. It is Toshiba's ownership of flash intellectual property that Kim said will set it apart from other manufacturers of hybrid drives.

For example, like Seagate's Momentus XT hybrid, Toshiba's drive will have self-learning caching algorithms, which overtime will determine what data should be stored on the flash and what should be stored only on the rotating media for long term access. All data that is written to the hybrid drive's flash cache is automatically written to spinning disk for resiliency, but if access to the data slows over time, it will be removed from cache and placed only on the spinning disk, Kim said. Data that's most frequently access will be kept on the 32MB of RAM, Kim said.

"Our self-learning caching algorithms are very sophisticated, such that we don't access the hard drive as frequently as we've witnessed with Seagate's Momentus XT," Kim said. "We think we have a superior solution."

Kim said the drive can go from hibernating state to live state in under 7 seconds.

"Some [computer manufacturers] have said we have the best-in-class in terms of responsiveness," Kim said.

One detriment attributed to hybrid drives is their use of mechanics, which can break if a laptop is dropped or jarred. Kim said Toshiba's upcoming hybrid comes with its long-used free-fall sensors, also known as accelerometers, which detect a fall and disengages the read-write head to protect it from impact.

"The technology is very sophisticated. We've been able to been able to tune our Free-fall sensors for a fall as low as 4 inches above a desktop," she said.

While Toshiba is starting with a hybrid drive aimed at Ultrabooks, Kim said the company will expand into other markets, such as full-sized laptops, and possibly desktops someday.

The price

Kim would not disclose a suggested retail price for the dirve, saying that the hybrid will be "competitive" with hard disk drives and Seagate's Momentus XT in price.

Kim said the drive will run for around $.14 cents or less per gigabyte of capacity. That would indicate that a 1TB version of the drive would sell for around $140. By comparison, Seagate's 750GB Momenus XT hybrid drive currently sells for $195 to $324 on online retail sites.